#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>

int global_value = 100;

int main()
{
    pid_t id = fork();
    if (id < 0)
    {
        printf("fork error\n");
        return 1;
    }
    if (id == 0)
    {
        int cnt = 0;
        while (1)
        {
            printf("子进程,pid:%d ppid:%d | global_value:%d,&global_value: %p\n", getpid(), getppid(), global_value, &global_value);
            sleep(1);
            cnt++;
            if (cnt == 10)
            {
                global_value = 300;
                printf("子进程已经更改了全局变量了！！！\n");
            }
        }
    }
    else
    {
        while (1)
        {
            printf("父进程,pid:%d ppid:%d | global_value:%d,&global_value: %p\n", getpid(), getppid(), global_value, &global_value);
            sleep(2);
        }
    }
    return 0;
}